#include <bits/stdc++.h>
using namespace std;
// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e9
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
#define sz size()
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
// input
template<class T> void IN(T& x) {cin >> x;}
template<class H, class... T> void IN(H& h, T&... t) {IN(h); IN(t...); }
// output
template<class T1, class T2> void OUT(const pair<T1,T2>& x);
template<class T> void OUT(const T& x) {cout << x;}
template<class H, class... T> void OUT(const H& h, const T&... t) {OUT(h); OUT(t...); }
template<class T1, class T2> void OUT(const pair<T1,T2>& x) {OUT(x.fi,' ',x.se);}
template<class... T> void OUTL(const T&... t) {OUT(t..., "\n"); }
template<class H> void OUTLS(const H& h) {OUTL(h); }
template<class H, class... T> void OUTLS(const H& h, const T&... t) {OUT(h,' '); OUTLS(t...); }
//===================//
// Added libraries //
//===================//
//===================//
//end added libraries//
//===================//
void program();
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
program();
}
//===================//
// begin program //
//===================//
const int MX = 1e5+2;
const int MX2 = 2e5+2;
int n, m;
int p[MX2], r[MX2];
vi adj[MX];
void buildDSU(int N) {
RE(i,N) p[i]=i, r[i]=1;
}
int get(int i) {return i==p[i] ? i : p[i] = get(p[i]);}
bool isSameSet(int i, int j) {return get(i)==get(j);}
void unionSet(int i, int j) {
i = get(i), j = get(j);
if(r[i] > r[j]) {
p[j] = i;
} else {
p[i] = j;
if(r[i] == r[j]) r[j]++;
}
}
int cnt=0;
void dfs(int u) {
if(r[u] != -1) return;
r[u] = r[u+n] = ++cnt;
RE(i,adj[u].sz) {
bool dup = 0;
if(i+1 != adj[u].sz && adj[u][i+1] == adj[u][i]) dup = 1;
if(r[adj[u][i]] == -1) {
p[adj[u][i]] = u;
dfs(adj[u][i]);
if(r[adj[u][i]+n] > r[u] && !dup)
OUTLS(u+1, adj[u][i]+1);
r[u+n] = min(r[u+n], r[adj[u][i]+n]);
} else if(adj[u][i] != p[u]) {
r[u+n] = min(r[u+n], r[adj[u][i]]);
}
if(dup) i++;
}
}
void program() {
IN(n, m);
buildDSU(n*2);
RE(i,m) {
int u, v; IN(u, v); u--; v--;
if(!isSameSet(u,v)) {
unionSet(u,v);
adj[u].pb(v);
adj[v].pb(u);
} else if(!isSameSet(u+n,v+n)) {
unionSet(u+n, v+n);
adj[u].pb(v);
adj[v].pb(u);
}
}
RE(i,n) sort(all(adj[i]));
RE(i,n) p[i] = -1, r[i] = -1;
RE(i,n) dfs(i);
}
Compilation message
pipes.cpp: In function 'void dfs(int)':
pipes.cpp:93:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
93 | if(i+1 != adj[u].sz && adj[u][i+1] == adj[u][i]) dup = 1;
| ^
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
2688 KB |
Output is correct |
2 |
Correct |
2 ms |
2688 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
7 ms |
3200 KB |
Output is correct |
2 |
Correct |
6 ms |
2944 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
117 ms |
3064 KB |
Output is correct |
2 |
Correct |
116 ms |
2940 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
197 ms |
3796 KB |
Output is correct |
2 |
Correct |
211 ms |
3276 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
317 ms |
5500 KB |
Output is correct |
2 |
Correct |
255 ms |
5112 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
429 ms |
10756 KB |
Output is correct |
2 |
Correct |
389 ms |
7288 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
666 ms |
11980 KB |
Output is correct |
2 |
Correct |
638 ms |
9208 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
886 ms |
14396 KB |
Output is correct |
2 |
Correct |
852 ms |
9644 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1110 ms |
14272 KB |
Output is correct |
2 |
Correct |
1026 ms |
10000 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1286 ms |
13632 KB |
Output is correct |
2 |
Correct |
1230 ms |
10872 KB |
Output is correct |